CN117460931A - Device comprising a weighing apparatus - Google Patents
Device comprising a weighing apparatus Download PDFInfo
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- CN117460931A CN117460931A CN202280041459.9A CN202280041459A CN117460931A CN 117460931 A CN117460931 A CN 117460931A CN 202280041459 A CN202280041459 A CN 202280041459A CN 117460931 A CN117460931 A CN 117460931A
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- weighing
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- 238000005303 weighing Methods 0.000 title claims abstract description 284
- 238000005259 measurement Methods 0.000 claims abstract description 147
- 230000002452 interceptive effect Effects 0.000 claims description 79
- 230000007246 mechanism Effects 0.000 claims description 22
- 239000004065 semiconductor Substances 0.000 claims description 21
- 238000000034 method Methods 0.000 claims description 19
- 230000008859 change Effects 0.000 claims description 17
- 238000012935 Averaging Methods 0.000 claims description 6
- 238000007664 blowing Methods 0.000 claims description 4
- 238000004364 calculation method Methods 0.000 claims description 3
- 239000003990 capacitor Substances 0.000 claims description 3
- 235000012431 wafers Nutrition 0.000 description 61
- 230000005291 magnetic effect Effects 0.000 description 11
- 230000005484 gravity Effects 0.000 description 10
- 238000004519 manufacturing process Methods 0.000 description 10
- 238000005452 bending Methods 0.000 description 6
- 230000001276 controlling effect Effects 0.000 description 6
- 238000012545 processing Methods 0.000 description 6
- 238000010586 diagram Methods 0.000 description 5
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 4
- 230000005670 electromagnetic radiation Effects 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 229910052710 silicon Inorganic materials 0.000 description 4
- 239000010703 silicon Substances 0.000 description 4
- 230000000087 stabilizing effect Effects 0.000 description 4
- 230000003094 perturbing effect Effects 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 238000013459 approach Methods 0.000 description 2
- 230000000903 blocking effect Effects 0.000 description 2
- 230000000875 corresponding effect Effects 0.000 description 2
- 230000001419 dependent effect Effects 0.000 description 2
- 230000005294 ferromagnetic effect Effects 0.000 description 2
- 238000003908 quality control method Methods 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 230000004044 response Effects 0.000 description 2
- 238000004804 winding Methods 0.000 description 2
- 238000003486 chemical etching Methods 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 230000002596 correlated effect Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000007717 exclusion Effects 0.000 description 1
- 230000003116 impacting effect Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000005305 interferometry Methods 0.000 description 1
- 238000005468 ion implantation Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 238000004377 microelectronic Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000000206 photolithography Methods 0.000 description 1
- 238000000623 plasma-assisted chemical vapour deposition Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01G—WEIGHING
- G01G7/00—Weighing apparatus wherein the balancing is effected by magnetic, electromagnetic, or electrostatic action, or by means not provided for in the preceding groups
- G01G7/02—Weighing apparatus wherein the balancing is effected by magnetic, electromagnetic, or electrostatic action, or by means not provided for in the preceding groups by electromagnetic action
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01G—WEIGHING
- G01G1/00—Weighing apparatus involving the use of a counterweight or other counterbalancing mass
- G01G1/18—Balances involving the use of a pivoted beam, i.e. beam balances
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01G—WEIGHING
- G01G21/00—Details of weighing apparatus
- G01G21/22—Weigh pans or other weighing receptacles; Weighing platforms
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01G—WEIGHING
- G01G21/00—Details of weighing apparatus
- G01G21/28—Frames, Housings
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01G—WEIGHING
- G01G23/00—Auxiliary devices for weighing apparatus
- G01G23/18—Indicating devices, e.g. for remote indication; Recording devices; Scales, e.g. graduated
- G01G23/36—Indicating the weight by electrical means, e.g. using photoelectric cells
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01G—WEIGHING
- G01G23/00—Auxiliary devices for weighing apparatus
- G01G23/18—Indicating devices, e.g. for remote indication; Recording devices; Scales, e.g. graduated
- G01G23/38—Recording and/or coding devices specially adapted for weighing apparatus
- G01G23/42—Recording and/or coding devices specially adapted for weighing apparatus electrically operated
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
- H01L21/67005—Apparatus not specifically provided for elsewhere
- H01L21/67242—Apparatus for monitoring, sorting or marking
- H01L21/67253—Process monitoring, e.g. flow or thickness monitoring
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L22/00—Testing or measuring during manufacture or treatment; Reliability measurements, i.e. testing of parts without further processing to modify the parts as such; Structural arrangements therefor
- H01L22/10—Measuring as part of the manufacturing process
- H01L22/12—Measuring as part of the manufacturing process for structural parameters, e.g. thickness, line width, refractive index, temperature, warp, bond strength, defects, optical inspection, electrical measurement of structural dimensions, metallurgic measurement of diffusions
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- Weight Measurement For Supplying Or Discharging Of Specified Amounts Of Material (AREA)
- Electric Ovens (AREA)
Abstract
An apparatus comprising: a weighing apparatus for generating a measurement output indicative of the weight of an object loaded on the weighing apparatus; and a disturbing element for temporarily disturbing the measurement output of the weighing apparatus when an object is loaded on the weighing apparatus.
Description
Technical Field
The present invention relates to an apparatus comprising a weighing device for generating a measurement output indicative of the weight of an object, such as a semiconductor wafer, loaded on the weighing device.
Background
Microelectronic devices are fabricated on semiconductor (e.g., silicon) wafers using a variety of techniques including, for example, deposition techniques (CVD, PECVD, PVD, etc.) and removal techniques (e.g., chemical etching, CMP, etc.). The semiconductor wafer may be further processed in a manner that alters the quality of the semiconductor wafer, such as by cleaning, ion implantation, photolithography, and the like.
Depending on the equipment being manufactured, each semiconductor wafer may be sequentially subjected to hundreds of different processing steps to create and/or remove the layers and materials required for its final operation. In practice, each semiconductor wafer passes through a production line. The nature of semiconductor manufacturing means that certain process steps or sequences of steps in a production flow may be repeated in a similar or identical manner. This may be, for example, to build similar metal conductor layers to interconnect different portions of the active circuitry.
To ensure consistency and interoperability of semiconductor devices used in different factories, most semiconductor manufacturing industries employ standards. For example, standards developed by the semiconductor equipment materials industry association (SEMI) have a high degree of market acceptance. Examples of standardization are the size and shape of semiconductor (silicon) wafers: typically for mass production they are discs with a diameter of 300 mm. However, some semiconductor (silicon) wafers (commonly used in older factories) are disks with a diameter of 200 mm.
The cost and complexity of the processing steps required to produce a complete silicon wafer and the time taken to reach the end of the production line (where its operation can be properly assessed) result in the need to monitor the operation of the production line equipment and the quality of the wafers being processed throughout the process so that the reliability of the performance and yield of the final wafer can be ensured.
Wafer processing techniques typically result in variations in quality at or on the surface of a semiconductor wafer. The varying configuration of the surfaces is often critical to the functioning of the apparatus, and therefore it is necessary to evaluate the wafers during production for quality control purposes to determine whether they have the correct configuration.
Specialized metrology tools may be used in the production flow so that monitoring occurs shortly after the relevant process of interest and typically prior to any subsequent processing (i.e., between processing steps).
Measuring the mass change of the wafer on either side of the process step is an attractive method for implementing product wafer metrology. The method is relatively low cost, fast and automatically adaptable to different wafer circuit patterns. Furthermore, this approach may generally provide higher accuracy results than alternative techniques. For example, on many common materials, the thickness of a material layer may decompose to an atomic scale. The relevant wafers are weighed before and after the process step of interest. The change in quality is correlated to the performance of the production device and/or the desired properties of the wafer.
More accurate measurement of the mass change of the wafer allows for tighter quality control of the wafer processing.
The mass of the wafer can be measured by first loading the wafer onto the load cell. When a wafer is loaded on the force-measuring device, the output of the force-measuring device will wander before stabilizing at a stable value. The stable value may then be converted to a mass value via application of buoyancy calculations.
However, if the same wafer is repeatedly placed on the same force-measuring device, the stable value will be different each time the output of the force-measuring device is stable due to the variable error of the output of the force-measuring device.
It is desirable to reduce the variable error of the output of the load cell to allow for a more accurate measurement of the mass change of the wafer.
Variations in the output of the force-measuring device can be reduced by performing multiple measurements on the wafer and averaging the output of the force-measuring device over all the multiple measurements.
However, once the output of the load cell has stabilized at a stable value, the output of the load cell remains the same when a wafer is loaded on the load cell. In other words, the output of the force-measuring device locks once it has become stable. Thus, if the output has stabilized by performing a number of measurements while the wafer is loaded on the load cell, the output of the load cell will be the same for all measurements and the average measurement will not reduce the variable error of the output of the load cell.
Thus, in order to reduce the variable error in the output of the force-measuring device by averaging the output of the force-measuring device over all multiple measurements, there is currently a need to remove the wafer from the force-measuring device between each measurement, while allowing the output of the force-measuring device to return to zero before reloading the wafer onto the force-measuring device to perform the next measurement.
With this solution, the value at which the output of the force-measuring device stabilizes will be different each time, due to the variable error of the output of the force-measuring device, and the variable error can be reduced by averaging the outputs of all the multiple measured force-measuring devices.
Disclosure of Invention
The inventors have realized that while the above described approach is effective for reducing the variable error of the output of the load cell, it is time consuming and thus affects wafer throughput.
In particular, the process of lifting the wafer from the load cell, waiting for reading back to zero, loading the wafer back onto the load cell, and waiting for the output of the load cell to stabilize between each measurement is time consuming.
The present invention may provide a less time consuming solution for reducing the variable error of the output of the force-measuring device.
The inventors have realized that although once the output has stabilized, the output of the force-measuring device appears to lock at a stable value, if the wafer and/or the force-measuring device are sufficiently disturbed, the measured output will change and will then stabilize at a different stable value due to the variable error of the output of the force-measuring device.
The inventors have realized that by temporarily and controllably perturbing the measurement output of the weighing apparatus when loading semiconductor wafers on the weighing apparatus, multiple measurements can thus be obtained faster that can be averaged to reduce the variable error of the output of the load cell.
In particular, the measured output of the weighing apparatus is temporarily disturbed significantly faster when loading the semiconductor wafer on the weighing apparatus than when lifting the wafer from the load cell, waiting for reading back to zero, loading the wafer back onto the load cell, and waiting for the output of the load cell to settle at a new value.
Of course, the solution can also be applied to objects weighing non-semiconductor wafers. The term object may therefore be used, where appropriate, to replace the references below to wafers or semiconductor wafers.
The solution is also applicable to weighing devices comprising different types of force sensors, force transducers, or force measuring devices.
A force sensor may refer to a force sensor or a force transducer configured to convert a force applied to the force sensor or the force transducer into an electrical signal corresponding to the force.
Thus, in its most general terms, the present invention relates to providing a weighing apparatus having means for temporarily interfering with the output of the weighing apparatus when an object is loaded on the weighing apparatus.
According to the present invention there is provided an apparatus comprising:
a weighing apparatus for generating a measurement output indicative of the weight of an object loaded on the weighing apparatus; and
means for temporarily disturbing the measurement output of the weighing apparatus when an object is loaded on the weighing apparatus.
The device according to the invention may have any one of the following optional features, or any combination of the following optional features, if compatible.
The term object or item may be used instead of the term object.
The object may be a wafer-shaped article, such as a wafer, for example a semiconductor wafer.
The device may be used for determining information about or indicative of the weight of the object, or for determining information about or indicative of the mass of the object.
The device may be used to determine the weight of an object.
The device may be used to determine the mass of the object, or the difference between the mass of the object and a reference mass.
The measured output indicative of the weight of the object may mean the measured weight of the object, or the difference between the weight of the object and the weight of another item, such as a reference weight.
The measurement output may be the weight of the object, or the difference between the weight of the object and the weight of another item, for example a reference weight.
The measurement output indicative of the weight of the object may mean a measurement output corresponding to the weight of the object.
Generating a measurement output indicative of the weight of the object loaded on the weighing apparatus may include performing a weight measurement on the object loaded on the weighing apparatus, or a gravity measurement on the object loaded on the weighing apparatus.
The weighing apparatus may have a measurement zone on which objects are loaded, for example a pan such as a balance pan or a weighing pan.
The weighing apparatus may be configured, or applied, to produce a measurement output indicative of the weight of an object loaded on the weighing apparatus.
The disturbing element may be configured, or applied, to temporarily disturb the measurement output of the weighing apparatus when an object is loaded on the weighing apparatus.
The weighing apparatus may have a pan, such as a balance pan (or weighing pan), for supporting the object during the time the weighing apparatus performs the measurement.
The weighing apparatus may comprise or may be a microbalance.
The weighing apparatus may comprise or be a weighing scale.
The weighing apparatus may comprise or may be an electronic balance.
The weighing apparatus may comprise a force sensor or force transducer for generating a measurement output indicative of the weight of an object loaded on the weighing apparatus.
The weighing apparatus may include a gravity sensor or a gravity transducer for generating a measurement output indicative of the weight of an object loaded on the weighing apparatus.
The weighing apparatus may comprise a force-measuring device for generating a measurement output indicative of the weight of an object loaded on the weighing apparatus.
The measurement zone (e.g., disk) may be connected or coupled to a force sensor, force transducer, gravity sensor, gravity transducer, or force measuring device such that gravity of an object loaded on the measurement zone is transferred from the measurement zone to the force sensor, force transducer, gravity sensor, gravity transducer, or force measuring device.
The weighing apparatus may generate a measurement output based on a measurement of an amount of electromagnetic force compensation required to compensate (or counter) the weight loaded on the weighing apparatus.
The weighing apparatus may be configured to balance the weight of an object with the forces to which the electromagnetic coil of the weighing apparatus is subjected when energized in the magnetic field of the weighing apparatus. In particular, the weighing apparatus may be configured to provide an electrical current to the electromagnetic coil sufficient to balance the force experienced by the electromagnetic coil against the weight of the object. The measurement output of the weighing device may be generated based on the required current. The weighing device may thus comprise an electromagnetic coil arranged in a magnetic field.
The weighing device may comprise an electromagnetic force compensation or electromagnetic force restoration force sensor or force measuring device with an electromagnetic coil.
The electromagnetic coil may be a winding wound around an iron core, such as a ferromagnetic core.
The term electromagnetic may mean an electromagnetic coil, or a winding of an electromagnetic coil wound around an iron core, such as a ferromagnetic core.
Disturbing the measurement output of the weighing apparatus may mean causing a change or variation of the measurement output.
In particular, a measurement output that interferes with the weighing apparatus may mean another predetermined measurement output that causes the measurement output to change or fluctuate without the measurement output returning to zero or being produced by the weighing apparatus when no object is loaded on the weighing apparatus.
The disturbance element controllably disturbs the measurement output of the weighing apparatus.
The apparatus may comprise a controller for controlling (or configured or applied to control) the disturbance element to controllably and temporarily disturb the measurement output of the weighing device.
The measurement output of the disturbance weighing device may mean a disturbance measurement output, or an interferometry measurement output, or an interruption measurement output, or a disturbance measurement output, or a change measurement output, or an alternation measurement output.
The interfering element may be an interfering arrangement, or an interfering mechanism, or an interfering article, or an interfering component, or an interfering device.
Disturbing the measurement output of the weighing apparatus when an object is loaded on the weighing apparatus means disturbing the measurement output without removing the object from the weighing apparatus. In other words, the object is loaded on the weighing device during disturbances of the measurement output.
There may be many different ways of interfering with the measurement output of the weighing apparatus, and the invention is not limited to a particular way of interfering with the measurement output. Some exemplary schemes are discussed below, but the invention is not limited to these specific examples.
The interfering element may comprise an actuator, such as an electronic or pneumatic actuator.
The interfering element may comprise a contact element configured to temporarily contact the weighing device and/or the object. The contact element may be movable, for example by means of an actuator, to cause the contact element to temporarily contact the weighing device and/or the object. The apparatus may thus comprise an actuator configured to move the contact element to temporarily contact the weighing device and/or the object. The apparatus may include a controller configured to control movement of the contact element to temporarily contact the weighing device and/or the object.
For example, the contact element may comprise a pin or a rod for temporarily contacting the weighing device and/or the object.
The interfering element may be configured to interfere with an object loaded on the weighing apparatus.
For example, the interfering element may be configured to cause movement of an object loaded on the weighing apparatus.
For example, the interfering element may comprise a contact element movable, for example by an actuator of the device, to temporarily contact an object loaded on the weighing apparatus in order to cause movement of the object. The apparatus may include a controller configured to control movement of the contact element to temporarily contact an object loaded on the weighing device to cause movement of the object.
Additionally, or alternatively, the interfering element may be configured to apply a force to an object loaded on the weighing apparatus.
For example, the interfering element may comprise a contact element movable, for example by an actuator of the device, to temporarily contact the object to apply a force to the object. The device may include a controller configured to control movement of the contact element to temporarily contact the object to apply a force to the object.
The interfering element may be configured to apply a force to the object in the direction of gravity of the object, or at least partly in the direction of gravity of the object, in order to increase the total force measured by the weighing device. For example, the interfering element may comprise a contact element movable, for example by an actuator of the device, to temporarily apply a force to the top of the object (the surface of the object opposite the weighing device).
Alternatively, the interfering element may be configured to apply a force to the object in a direction opposite to the weight force of the object, or at least partially in a direction opposite to the weight force of the object, in order to reduce the total force measured by the weighing apparatus. For example, the interfering element may comprise a contact element movable, for example by an actuator of the device, to temporarily apply a force to the bottom of the object (facing the weighing device).
The interference element may be configured to interfere with the weighing apparatus, or a component of the weighing apparatus.
For example, the interference element may be configured to interfere with a measuring area of a pan (balance pan or weighing pan) of the weighing device, for example, and/or a force sensor, force transducer or force measuring device of the weighing device.
For example, the interfering element may be configured to cause movement of the weighing apparatus or a component of the weighing apparatus.
For example, the interfering element may comprise a contact element movable, for example by an actuator of the device, to temporarily contact the weighing apparatus or a component of the weighing apparatus in order to cause movement of the weighing apparatus or the component of the weighing apparatus. The apparatus may include a controller configured to control movement of the contact element to temporarily contact the weighing device or a component of the weighing device to cause movement of the weighing device or the component of the weighing device.
Additionally, or alternatively, the interfering element may be configured to apply a force to the weighing apparatus or a component of the weighing apparatus.
For example, the disturbance element may be configured to temporarily apply a force to a measurement area of the weighing device, such as a pan, or to a force sensor, force transducer or force measuring device of the weighing device. In particular, the interfering element may comprise a contact element movable, for example by an actuator, to temporarily contact a component of the weighing device to apply a force to the component of the weighing device. The apparatus may include a controller configured to control movement of the contact element to temporarily contact a component of the weighing device to apply a force to the component of the weighing device.
The force applied to the weighing apparatus or to a component of the weighing apparatus may be configured to increase the weight force measured by the weighing apparatus or to decrease the weight force measured by the weighing apparatus.
The disturbing element may be configured to temporarily apply a force to a measuring area of the weighing device, such as a balance, in the direction of the weight of the object, or at least partly in the direction of the weight of the object, in order to increase the force measured by the weighing device. For example, the interfering element may comprise a contact element movable, for example by an actuator of the device, to temporarily apply a force to the top of the measurement zone. The device may include a controller configured to control movement of the contact element to temporarily apply a force to the top of the measurement zone.
Alternatively, the interfering element may be configured to temporarily apply a force to the measurement zone in a direction opposite to the gravitational force of the object, or at least partially in a direction opposite to the gravitational force of the object, in order to reduce the total force measured by the weighing apparatus. For example, the disturbing element may comprise a contact element movable, for example by an actuator, to temporarily apply a force to the bottom of the measurement zone. The device may include a controller configured to control movement of the contact element to temporarily apply a force to the bottom of the measurement zone.
The interfering member may be configured to change the total weight loaded on the weighing apparatus. For example, the interfering element may temporarily support the weight of a portion of the object, or temporarily apply a force to the object to increase the loading force on the weighing apparatus. This may be achieved by a disturbing element comprising a contact element movable, for example by an actuator of the device, to temporarily contact the object and apply a force to the object. The device may include a controller configured to control movement of the contact element to temporarily contact the object and apply a force to the object. Alternatively, the interfering element may load additional weight on the weighing device internally or externally. This can be achieved by the interfering element comprising an additional weight loaded onto the measuring area of the weighing device by the loading mechanism. The interfering element may thus comprise a load and a loader for loading and unloading the load on the weighing device, for example by loading and unloading the load on a measuring area of the weighing device. The apparatus may include a controller configured to control the loader to load and unload the load on the weighing device.
The interfering element may comprise a lifting pin lifting the weight of the object of the part. For example, the lifting pin is movable, e.g. by an actuator of the device, to temporarily contact the underside of the object and apply a lifting force to the object to counteract part of the weight of the object. The apparatus may include a controller configured to control movement of the lift pins to temporarily contact an underside of the object and apply lift to the object to counteract a portion of the weight of the object. The lifting pins may lift the weight of only a portion of the object so that the object remains loaded on the weighing apparatus.
The disturbance element may comprise an element or actuator providing a counter-force to the object and/or the weighing device, for example by impacting the object and/or the weighing device (e.g. a force sensor or force measuring device of the weighing device).
For example, the interfering element may comprise a contact element or impact element movable, e.g. by an actuator of the device, to temporarily contact or impact the object and/or the weighing device to provide a counter force to the object and/or the weighing device. As discussed above, the counter-force may be applied at least partially in the direction of the weight of the object, or at least partially in a direction opposite to the weight of the object. The apparatus may include a controller configured to control movement of the contact element or impact element to temporarily contact or impact the object and/or the weighing device to provide a counter-force to the object and/or the weighing device.
The weighing apparatus may comprise an electromagnetic coil; and the interfering element may comprise a magnet or a solenoid that is operable to interfere with the solenoid of the weighing apparatus.
The weighing device may comprise a force-measuring device with an electromagnetic coil of the weighing device.
The magnets may be permanent magnets that are movable closer to, or further away from, the electromagnetic coil. For example, the interfering element may comprise an actuator for moving the magnet closer to, or further away from, the electromagnetic coil of the weighing device. The device may include a controller configured to control the magnet to move closer to, or further away from, the solenoid. Alternatively, the magnet may be an electromagnet. For example, an electromagnet may be arranged around the electromagnetic coil of the weighing device. The interfering element may thus comprise a power source for selectively supplying current to the electromagnet. The apparatus may include a controller configured to control the power supply to selectively and/or temporarily supply current to the electromagnet. Where the interfering element comprises a solenoid, the solenoid may be wound around the solenoid of the weighing apparatus, or positioned or placed around the solenoid of the weighing apparatus. The interfering element may thus comprise a power source for selectively supplying current to the electromagnetic coil of the interfering element. The apparatus may include a controller configured to control the power source to selectively and/or temporarily supply current to the solenoid.
The weighing apparatus may comprise a force-measuring device and the magnet may be an electromagnet which surrounds the force-measuring device when the electromagnet is energized. The measurement output of the weighing device can thus be temporarily disturbed by temporarily energizing the electromagnet.
The weighing apparatus may comprise a force-measuring device. The disturbance element may comprise a magnet (e.g. a permanent magnet or an electromagnet) or an electromagnetic coil, which may be used to disturb the force-measuring device. For example, the device may include a controller configured to temporarily supply current to the electromagnetic coil so as to interfere with the force-measuring device. Additionally, or alternatively, the device may comprise an actuator for moving the magnet or electromagnetic coil closer to, or further away from, the force-measuring device so as to interfere with the force-measuring device. The apparatus may include a controller configured to control movement of the magnet or solenoid.
The force-measuring device may comprise, for example, a solenoid as described above.
The weighing apparatus may balance the downward force of the weight of the object with the force experienced by the electromagnetic coil when energized in the magnetic field. The use of a magnet or an electromagnetic coil to interfere with the electromagnetic coil will thus interfere with the measurement output of the weighing apparatus.
For example, the weighing device may comprise an electromagnetic force compensation or electromagnetic force restoration force sensor or force measuring device with an electromagnetic coil.
The interfering element may comprise a mechanism for temporarily loading additional weight on the weighing device.
The interfering element may comprise a blower, such as a fan, for blowing air at or on the object. The apparatus may include a controller configured to selectively and/or temporarily activate the blower to blow air at or on the object.
The device or weighing apparatus may comprise a measurement chamber; and the disturbing element may comprise a mechanism for disturbing the air in the measuring chamber.
For example, the interfering element may comprise a blower, such as a fan, for blowing air inside the measurement chamber.
The interfering element may comprise a controller configured to temporarily open and then close a lid of the measurement chamber to interfere with air in the measurement chamber. The device may thus comprise a measuring chamber enclosing the weighing apparatus, wherein the lid of the measuring chamber is openable or detachable. The device may further comprise one or more actuators for opening or removing the lid of the measurement chamber. The apparatus may include a controller configured to control the cover to be opened or detached to temporarily interfere with a measurement output of the weighing apparatus when an object is loaded on the weighing apparatus. The controller may then control the lid to be closed or replaced before recording further measurement outputs.
The disturbance element may comprise a mechanism for vibrating the weighing device and/or the object.
The mechanism may comprise a vibrator and/or an actuator for vibrating the weighing apparatus and/or the object.
For example, the vibrator may be movable by an actuator of the apparatus to temporarily contact and cause to vibrate a weighing apparatus (e.g., a measurement zone of the weighing apparatus) or an object. Alternatively, the vibrator may be in contact with a component of the weighing apparatus and may be selectively and/or temporarily activated to vibrate the component of the weighing apparatus and/or the object. The device may include a controller configured to control movement and/or actuation of the vibrator.
The interfering element may comprise a mechanism for moving a component of the weighing device. For example, the disturbance element may move a force-measuring device or a solenoid of the weighing device. This may be achieved by the interference element comprising a contact element which is movable by an actuator of the device to contact a component of the weighing apparatus. The device may include a controller configured to control movement of the contact element. Alternatively, the apparatus may comprise an actuator attached to, or coupled to, or connected to a component of the weighing device, operable to move the component of the weighing device. The apparatus may include a controller configured to control movement of the components of the weighing device.
The interfering element may comprise a mechanism for mechanically interfering with the object and/or the weighing device. Mechanically disturbing the object and/or the weighing apparatus may mean physically contacting the object and/or the weighing apparatus to move and/or change the configuration of the object and/or the weighing apparatus. This can be achieved using the contact element and the actuator as described above.
The interfering element may comprise a device for temporarily interrupting or changing the power supplied to the weighing device. For example, the interfering element may comprise a switch for interrupting the power supply to the weighing device. The device may temporarily interrupt or change the power to the force-measuring device or the electromagnetic coil of the weighing device. Interrupting the power supply may mean temporarily turning off, or temporarily turning off, the power supply. The apparatus may include a controller configured to control a temporary interruption of the power supply to the weighing device. For example, the controller may control the switch to be on to temporarily interrupt the power supplied to the weighing apparatus and then to be off to no longer interrupt the power.
The disturbance element may include a controller configured to reset or interrupt a stability algorithm of the weighing apparatus. The stability algorithm may be software that stabilizes the output of the weighing apparatus when an object is loaded on the weighing apparatus. Thus, resetting or interrupting the stability algorithm may interfere with the output of the weighing apparatus.
The weighing apparatus may comprise a position sensor for detecting the position of a component of the weighing apparatus; and the interfering element may comprise a mechanism for optically or mechanically interfering with the position sensor.
The weighing apparatus may comprise a solenoid and the position sensor may detect the position of the solenoid or another component of the weighing apparatus that moves with the solenoid.
The weighing device may comprise a force-measuring cell with an electromagnetic coil.
For example, the weighing apparatus may balance the downward force of the weight of an object with the force experienced by the electromagnetic coil when energized in a magnetic field. The position sensor may detect the position of the electromagnetic coil or another component of the weighing apparatus that moves with the electromagnetic coil.
The position sensor may detect position using electromagnetic radiation, such as visible light. For example, the position sensor may include a light source (or other electromagnetic radiation source) and a photosensor (or other electromagnetic radiation sensor), wherein movement of the electromagnetic coil causes a change in the magnitude of light (or other electromagnetic radiation) detected by the photosensor.
The mechanically disturbed position sensor may comprise, for example, physically blocking (or partially blocking) the sensing path of the position sensor, or moving the light sensor part of the position sensor, or moving the light source part of the position sensor. The optical disturbance position sensor may include, for example, providing additional light to the light sensor.
The device may include a controller configured to control the mechanism to temporarily optically or mechanically interfere with the position sensor.
The weighing device may comprise a force-measuring device (or force sensor, or force transducer). The device may comprise circuitry for supplying power to the force-measuring device. The interfering element may comprise a mechanism or configuration or device or component for temporarily changing the electrical characteristics of the circuit.
The weighing apparatus may comprise the circuit.
The disturbance element may comprise a mechanism or configuration or device or component for temporarily changing an electrical characteristic of the circuit to change the current flowing through the force-measuring device.
For example, the interfering element may comprise a mechanism or configuration or device or component for temporarily increasing the electrical load, resistance, capacitance or inductance of the circuit, or for temporarily decreasing the electrical load, resistance, capacitance or inductance of the circuit.
The interfering element may comprise a mechanism or configuration or device or component for temporarily introducing an additional load, resistance, capacitance or inductance into the circuit, for example by temporarily adding an additional load, resistance, capacitance or inductance into the circuit.
Alternatively, the interfering element may comprise a mechanism or configuration or device or component for temporarily removing the load, resistance, capacitance or inductance from the circuit, for example by temporarily disconnecting the load, resistance, capacitance or inductance from the circuit.
The addition or removal of a load, a resistor, a capacitor or an inductance in the circuit may be controlled by the controller of the device in order to disturb the measurement output of the weighing apparatus.
Alternatively, the interfering element may comprise a controller of a device configured to temporarily adjust a variable load, a variable resistance, a variable capacitance, or a variable inductance load, resistance, capacitance, or inductance in the circuit.
The weighing device may comprise a force-measuring device (or force sensor, or force transducer). The disturbance element may comprise an electronic component and a switch in parallel with the force-measuring device.
The switch may be closed to turn on the electronic components in parallel with the force-measuring device and opened to turn off the electronic components in parallel with the force-measuring device.
The switch may be a relay, for example. The switch may be controllable by the controller to open or close the switch. The switch may be controlled via a wired connection or via a wireless connection.
The apparatus may include a controller configured to close the switch to temporarily interfere with an output of the weighing apparatus when an object is loaded on the weighing apparatus. The controller may be configured to subsequently open the switch before recording the further measured output.
The electronic components and the switch may be included in a circuit for supplying power to the force-measuring device.
The electronic component may include a load, a resistor, a capacitor, or an inductor. Of course, more than one of these electronic components may be included, and/or one or more different types of electronic components may be included.
The electronic component and the switch may be connected in series (in any order) and the series of electronic component and switch is connected in parallel with the force-measuring device.
Thus, when the switch is closed, the electronic component is connected in parallel with the force-measuring device and the current flowing through the force-measuring device will be reduced (because of the current flowing through the electronic component). In contrast, when the switch is opened, current cannot flow through the electronic components and thus the current flowing through the force-measuring device will not decrease.
Thus, by temporarily closing the switch, the current through the force-measuring device can be temporarily reduced. This may interfere with the measurement output of the weighing apparatus. The measurement output of the weighing device can then be stabilized on the new stabilized measurement output when the switch is opened.
The force-measuring device may comprise an electromagnetic coil and the circuit may be adapted to supply an electric current to the electromagnetic coil.
An electronic component and a switch may be connected in parallel with the electromagnetic coil.
The weighing device may comprise an electromagnetic force compensation or recovery force sensor or force measuring device, wherein the current is supplied to the electromagnetic coil when the electromagnetic coil is in an external magnetic field such that the force to which the electromagnetic coil is subjected balances the weight force of an object loaded on the weighing device. If the current through the solenoid is temporarily reduced by closing the switch, the measurement output of the weighing device will be disturbed.
The circuit may comprise a power supply or a current supply for supplying power or current to the force-measuring device.
The apparatus may include a controller configured to: recording a stable measurement output of the weighing apparatus with the object loaded on the weighing apparatus; controlling the disturbance element to temporarily disturb a measurement output of a weighing apparatus having an object loaded on the weighing apparatus; and recording a subsequent stable measurement output of the weighing apparatus with the object loaded on the weighing apparatus.
The controller may be configured to average the stable measurement output and the subsequent stable measurement output.
The controller may be configured to: repeating the steps of controlling the interfering element and recording the subsequent stable measurement output for a plurality of times; and averaging at least some of the stable measurement outputs and the subsequent stable measurement outputs.
The apparatus may include a controller configured to calculate a mass of the object based on the measured output.
The controller may be configured to convert the measurement output to a mass value via application of buoyancy calculations.
The interfering element may be included inside the weighing apparatus or may be external to the weighing apparatus.
The references above to controllers may be to a single controller performing multiple functions, or to more than one controller.
According to a second embodiment of the present invention there is provided a method comprising:
using the weighing apparatus to generate a measurement output indicative of the weight of an object loaded on the weighing apparatus; and
temporarily disturbing the measurement output of the weighing apparatus when an object is loaded on the weighing apparatus.
The method according to the second embodiment of the invention may have any of the features of the apparatus of the invention described above or below, unless incompatible.
For example, the weighing apparatus may have any of the features of the weighing apparatus described above or below.
The measuring output of the weighing device can be temporarily disturbed using a disturbing element. The interfering element may have any of the features of the interfering element described above or below.
The method may include recording a stable measurement output of the weighing apparatus with the object loaded on the weighing apparatus; temporarily disturbing the measurement output of the weighing apparatus when an object is loaded on the weighing apparatus; and recording a subsequent stable measurement output of the weighing apparatus with the object loaded on the weighing apparatus.
The method may include calculating an average measurement output based at least on the stable measurement output and the subsequent stable measurement output.
The method may include repeating the steps of temporarily perturbing the measurement output and recording the subsequent stable measurement output a plurality of times; and averaging at least some of the stable measurement outputs and the subsequent stable measurement outputs.
Drawings
By way of example only, embodiments of the present invention will now be discussed with reference to the accompanying drawings, in which:
FIG. 1 is a schematic diagram of a conventional electronic balance that may be used with embodiments of the present invention;
FIG. 2 is a schematic diagram of a conventional electronic balance that may be used with embodiments of the present invention;
FIG. 3 is a schematic diagram of an apparatus according to an embodiment of the invention; and
Fig. 4 is a schematic view of an apparatus according to a further embodiment of the invention.
Detailed Description
Embodiments and aspects of the invention will now be discussed with reference to the accompanying drawings. Further implementation aspects and embodiments will be apparent to those skilled in the art.
All documents mentioned herein are incorporated herein by reference.
Fig. 1 is a simplified schematic diagram of the major elements of a conventional electronic balance that may be used in embodiments of the present invention.
As shown in fig. 1, a conventional electronic balance 1 includes a balance beam 3. The balance beam 3 can be pivoted at a pivot point 5, for example a knife edge. The balance plate 7 is positioned on the balance beam 3 on the first side of the pivot point 5. On the second side of the pivot point 5, an electromagnet or solenoid 9 is positioned on the balance beam 3. The electromagnet or solenoid 9 is located within the magnetic field of the magnet 11. The magnet 11 may be a permanent magnet or an electromagnet.
In the use of a conventional electronic balance 1, an object (e.g., a semiconductor wafer) of which weight is to be measured is placed on a balance pan 7. The weight of the object on the balance pan 7 creates a moment on the balance beam 3, which moment is used to rotate the balance beam 3 around the pivot point 5 in a counter-clockwise direction. Rotation of the balance beam 3 about the pivot point 5 in a counter-clockwise direction will cause the electromagnet or solenoid 9 to move upwards.
When a current is supplied to the electromagnet or electromagnetic coil 9, the electromagnet or electromagnetic coil 9 generates a magnetic field. The interaction between the magnetic field generated by the electromagnet or electromagnetic coil 9 and the magnetic field generated by the magnet 11 causes the electromagnet or electromagnetic coil 9 to be subjected to a force, the magnitude and direction of which is determined by the magnitude and direction of the current applied to the electromagnet or electromagnetic coil 9.
By applying a current of a suitable magnitude and direction to the electromagnet or solenoid 9, the electromagnet or solenoid 9 is subjected to a downward force, resulting in a moment on the balance beam 3 that is equal in magnitude and opposite in direction to the moment caused by the weight of the object on the balance disc 7 (i.e. a moment in the clockwise direction in fig. 1). In this case the electromagnet or solenoid 9 will remain stationary and will not move upwards, since the two moments acting on the balance beam cancel, which means that there is no resultant moment.
The downward force on the electromagnet or solenoid 9 and thus the moment caused by the downward force is dependent on the magnitude of the current applied to the electromagnet or solenoid 9. Thus, by measuring the amount of current applied to the electromagnet or solenoid 9 that is required to hold the electromagnet or solenoid 9 in the same position when an object is placed on the balance disc 7, the moment caused by the weight of the object on the balance disc 7 can be determined. For example, the position of the electromagnet or electromagnetic coil 9 (or another part of the electronic balance 1 that moves with the electromagnet or electromagnetic coil 9) may be determined or directly measured with high accuracy using a light diode and a light source (not shown).
Thus, when an object is placed on the balance disc 7, the current required to be applied to the electromagnet or solenoid 9 in order to keep the electromagnet or solenoid 9 in the same position is directly related to the weight of the object and can be used to calculate the weight of the object.
Fig. 2 is a simplified schematic diagram of the principal elements of a second conventional electronic balance that may be used in embodiments of the present invention.
As shown in fig. 2, a conventional electronic balance 13 includes a balance plate 15 on a shaft 17. The shaft 17 is connected to a fixed (i.e. rigid and stationary) body 19 by means of a balance beam 21. The balance beam 21 is rigidly/firmly attached to the shaft 17 at one end of the balance beam 21 and to the stationary body 19 at the other end of the balance beam 21 by a bending point. The bending point is a point at which the balance beam 21 may flex and/or bend, for example, in response to a load applied to the balance pan 15. For example, the bending point may be a narrowing in the balance beam 21.
Thus, when a load is applied to the balance plate 15, the shaft 17 can be displaced downward in the vertical direction by the balance beam 21 flexing or bending at the bending point.
An electromagnet or solenoid 23 is positioned below the shaft 17. However, in other embodiments the electromagnet or electromagnetic coil 23 may be positioned elsewhere. The electromagnet or solenoid 23 is located within the magnetic field of the magnet 25. The magnet 25 may be a permanent magnet, or an electromagnet.
The weighing device 13 according to this embodiment operates in a similar manner to the embodiments described above.
Specifically, when an object such as a semiconductor wafer is loaded on the balance plate 15, in the absence of any balance force, the balance beam 21 is deflected or bent at a bending point due to a moment caused by the weight of the object, and the balance plate 15 and the shaft 17 are moved downward.
However, if a suitable current is applied to the electromagnet or solenoid 23 such that the electromagnet or solenoid 23 is subjected to a suitable downward force, such downward movement of the balance 15 and shaft 17 is prevented.
Thus, the current that needs to be applied to the electromagnet or solenoid 23 in order to keep the electromagnet or solenoid 23 and the balance disc 15 in the same position when an object is loaded on the balance disc 15 is indicative of the weight of the object.
Of course, the invention is not limited to an electronic balance as shown in fig. 1 or 2, and other types or configurations of electronic balances, force sensors, force transducers, or force measuring devices may be used in the invention instead of the electronic balances shown in fig. 1 and 2.
As discussed above, when an object such as a wafer is loaded on a measuring pan of an electronic balance, the output of the electronic balance wanders before stabilizing at a steady value. This stable value is different each time a wafer is loaded on the measuring disk due to variable errors in the output of the electronic balance.
Once the output of the electronic balance has stabilized at a stable value, the output remains constant while the wafer is loaded on the measurement tray. Specifically, the output of the electronic balance becomes locked at a stable value.
Fig. 3 shows an apparatus 27 according to an embodiment of the invention. The apparatus comprises a weighing device, which in this embodiment is identical to the electronic balance 13 shown in fig. 2 and described above. Thus, the device 27 may comprise the electronic balance 13 shown in fig. 2 and/or any of the features described above. However, in other embodiments a different electronic balance or weighing device may be used instead of those shown in fig. 3. For example, the weighing apparatus may be replaced as shown in fig. 1 or may have a different configuration than those shown in fig. 1 and 2.
Furthermore, the device 27 further comprises a disturbing element for disturbing the output of the electronic balance 13.
In this embodiment, the interfering element comprises an electromagnet or electromagnetic coil 29 located close to the electromagnet or electromagnetic coil 23 of the electronic balance 13. In fig. 3, an electromagnet or solenoid 29 is shown positioned to the side of the electromagnet or solenoid 23. However, in other embodiments, the electromagnet or solenoid 29 may alternatively be disposed around the electromagnet or solenoid 23 or positioned elsewhere proximate the electromagnet or solenoid 23.
When the electromagnet or solenoid 29 is sufficiently energized while the wafer (or other object) is loaded on the electronic balance 13, the output readings from the electromagnet or solenoid 23 are disturbed. Thereby causing the output of the electronic balance 13 to change from the set value.
When the electromagnet or solenoid 29 is subsequently de-energized, the output of the electronic balance 13 stabilizes back to a new setting that is different from the initial setting due to the variable error of the output of the electronic balance 13.
The time taken to interfere with the measured output of the weighing apparatus in this way is significantly less than the time required to remove the wafer from the electronic balance 13, wait for the output of the electronic balance 13 to return to zero, reload the wafer on the electronic balance 13 and then wait for the output to settle at a new value.
The current and duration of the energization of the solenoid 29 is optimized to create enough disturbance to generate a new weight reading while minimizing the recovery time required for the new weight reading.
The apparatus may include a controller for selectively and/or temporarily energizing the electromagnet or solenoid 29 (or configured to selectively and/or temporarily energize) so as to interfere with the measurement output of the electronic balance when an object is loaded on the electronic balance.
By repeatedly disturbing the measuring output of the weighing device 13 and outputting new set values, a plurality of different set values can be produced. The plurality of different settings may then be averaged to reduce or eliminate the variable error in the output of the electronic balance 13.
For example, the apparatus 27 may comprise a controller 30, the controller 30 being configured to control the apparatus 27 to perform the steps of: recording a stable measurement output of the weighing apparatus when the object is loaded on the weighing apparatus; controlling the disturbance element to temporarily disturb the measurement output of the weighing apparatus with the object loaded on the weighing apparatus by temporarily energizing the electromagnet or the electromagnetic coil 29 temporarily; and recording a subsequent stable measurement output of the weighing apparatus with the object loaded on the weighing apparatus.
The controller may be configured to average the recorded stable measurement output.
The controller may be configured to perform the steps of controlling the disturbance element to temporarily disturb the measurement output of the weighing apparatus with the object loaded on the weighing apparatus, and recording the subsequent stable measurement output of the weighing apparatus with the object loaded on the weighing apparatus a plurality of times to record a plurality of subsequent stable measurement outputs.
The controller may be configured to average some or all of the stable measurement outputs and subsequent stable measurement outputs.
In this way, a more accurate measurement output may be obtained while minimizing the time required to obtain multiple measurements. Thus, the yield of wafers can be improved.
In this embodiment, the interfering element may be a permanent magnet instead of the electromagnet or electromagnetic coil 29, wherein the permanent magnet is movable closer to the electromagnet or electromagnetic coil 23 and further away from the electromagnet or electromagnetic coil 23 to change the magnetic field of the permanent magnet to which the electromagnet or electromagnetic coil 23 is subjected.
The electromagnet or solenoid 29 in the device 27 is only one example of a tamper device that can be used in the present invention and many different types of tamper elements can be used in the present invention as described above. These interfering elements include, but are not limited to: loading additional weight onto the weighing device either internally or externally; the weight of the wafer (or other object) supporting the portion or applying a force to the wafer to increase the loading force on the weighing apparatus; blowing at or on the wafer; disturbing the air in the measuring chamber of the weighing device, for example by opening and closing a lid of the measuring chamber; physically moving or vibrating some or all of the weighing apparatus or wafer, such as moving or vibrating an electromagnet or solenoid in the weighing apparatus; interrupting the power supply to the weighing device; resetting or interrupting a load cell stability algorithm of the weighing apparatus; or a position sensor that interferes with the weighing apparatus, such as a position sensor that detects the position of an electromagnet or a solenoid in the weighing apparatus.
A specific type of interfering element is not necessary for the present invention. Conversely, only when a wafer (or other object) is loaded on the weighing apparatus, the interfering element causes sufficient interference to cause the output of the weighing apparatus to change from the set point.
An apparatus 31 according to a further embodiment of the invention is shown in fig. 4. The apparatus 31 comprises a weighing device, which in this embodiment is identical to the electronic balance 1 shown in fig. 1 and described above. The device 31 may thus comprise any of the features of the electronic balance 1 shown in fig. 1 and/or described above. However, in other embodiments a different electronic balance or weighing device may be used instead of the electronic balance shown in fig. 1. For example, the weighing apparatus may be replaced as shown in fig. 2, or may have a different configuration than those shown in fig. 1 and 2.
The magnet 11 of the electronic balance 1 is not shown in fig. 4, but in this embodiment the magnet 11 is included in the electronic balance 1.
The device 31 comprises a controller 33 for supplying current to the electromagnet or solenoid 9, the controller 33 may for example be referred to as a force-measuring device controller. For example, the controller 33 may be connected to the electromagnet or solenoid 9 by circuitry (e.g., via lines 35 and 37) to pass current through the electromagnet or solenoid 9.
The controller 33 and/or the electrical circuits (e.g. lines 35 and 37) may be components of the weighing apparatus 1. Alternatively, the controller 33 and/or the electrical circuit may be external to the weighing device 1.
As described above, by applying a current of an appropriate magnitude and direction to the electromagnet or solenoid 9, the electromagnet or solenoid 9 is subjected to a downward force, causing the moment on the balance beam 3 to be equal in magnitude and opposite in direction to the moment caused by the weight of the object on the balance disc 7 (i.e., the moment in the clockwise direction in fig. 4). In this case the electromagnet or solenoid 9 will remain stationary and will not move upwards, since the two moments acting on the balance beam 3 cancel, meaning that there is no resultant moment.
The downward force on the electromagnet or solenoid 9 and thus the moment caused by this downward force is dependent on the magnitude of the current applied to the electromagnet or solenoid 9. Thus, by measuring the amount of current applied to the electromagnet or solenoid 9 required to hold the electromagnet or solenoid 9 in the same position when an object is placed on the balance disc 7, the moment caused by the weight of the object on the balance disc 7 can be determined. For example, the position of the electromagnet or electromagnetic coil 9 (or another component of the electronic balance 1 that moves with the electromagnet or electromagnetic coil 9) may be determined or directly measured with high accuracy using a light diode and a light source (not shown).
The current that needs to be applied to the electromagnet or solenoid 9 in order to keep the electromagnet or solenoid 9 in the same position when an object is placed on the balance disc 7 is thus directly related to the weight of the object and can be used to calculate the weight of the object (or information about the weight of the object, such as the difference between the weight of the object and a reference weight).
The device 31 further comprises a load 39 (e.g. a resistor) connected in parallel with the electromagnet or electromagnetic coil 9 (i.e. connected between the lines 35 and 37 in parallel with the electromagnet or electromagnetic coil 9).
A switch 41 (or relay) is connected in series with the load 39. In other words, the series connection of the load 39 and the switch 41 is in parallel with the electromagnet or the electromagnetic coil 9.
The switch 41 may be controlled to be on or off by the controller 43, and the controller 43 may be referred to as a switch controller or a relay controller. Of course, in another embodiment, a single controller may perform the functions of controllers 33 and 43. In fig. 4 a wired connection between the switch 41 and the controller 43 is shown, but in other embodiments the connection may of course be wireless.
The load 39, switch 41 and controller 43 may correspond to the interfering elements in this embodiment.
During operation of the electronic balance 1 to perform a measurement of an object loaded on the balance pan 7, the switch 41 is controlled by the controller 43 to be on so that current cannot flow through the load 39 in parallel with the electromagnet or the electromagnetic coil 9.
As discussed above, when an object such as a wafer is loaded on the balance pan 7 of the electronic balance 1, the output of the electronic balance 1 wanders before stabilizing at a stable value. This stable value differs each time a wafer is loaded on the balance disk 7 due to a variable error in the output of the electronic balance 1.
Once the output of the electronic balance 1 has stabilized at a stable value, the output remains fixed while the wafer is loaded on the balance disk 7. Specifically, the output of the electronic balance 1 becomes locked at a stable value.
The output of the electronic balance 1 becomes locked in correspondence with the controller 33 supplying a specific, fixed current to the electromagnet or electromagnetic coil 9.
Once the output of the electronic balance 1 has stabilized at a stable value and the stable value has been recorded, the controller 43 is configured to control the switch 41 to be off such that a current flows through the load 39 in parallel with the electromagnet or solenoid 9.
This means that less current will flow through the electromagnet or solenoid 9 and the electromagnet or solenoid 9 will therefore no longer remain in the same position. As in the example described above, the movement of the electromagnet or solenoid 9 will be detected and the controller 33 will, in response, by increasing the current supplied by the controller 33, interfere with the measurement output of the electronic balance 1 as described above.
Once the measured output of the electronic balance 1 has been disturbed in this way, the controller 43 is configured to control the switch 41 to be on such that current cannot flow through the load 39 in parallel with the electromagnet or the electromagnetic coil 9. The measured output of the electronic balance 1 will then wander before stabilizing at a stable value, possibly different from the previous stable value.
The second stable value will be recorded and the stable values can be averaged to produce an average measurement output.
The controller 43 thus controls the switch 41 to be off so as to interfere with the measurement output of the electronic balance 1 when an object is loaded on the electronic balance 1.
The process of temporarily perturbing the measurement outputs and recording the subsequent stable measurement outputs may be repeated multiple times to produce multiple measurement outputs, and then some or all of the measurement outputs may be averaged to produce an average measurement output.
For example, as described above with respect to the first embodiment, the apparatus 31 may comprise a controller (which may be the controller 43 or another controller) configured to control the apparatus 31 to perform the steps of: recording a stable measurement output of the weighing apparatus with the object loaded on the weighing apparatus; the control switch 41 is temporarily closed to temporarily interfere with the measurement output of the weighing apparatus having the object loaded on the weighing apparatus; control switch 41 to be subsequently opened in the case of having an object loaded on the weighing apparatus; and recording a subsequent stable measurement output of the weighing apparatus with the object loaded on the weighing apparatus.
The controller may be configured to average the recorded stable measurement output.
The controller may be configured to perform the steps of controlling the switch 41 to temporarily interfere with the measurement output of the weighing apparatus having an object loaded on the weighing apparatus and to record a subsequent stable measurement output of the weighing apparatus having an object loaded on the weighing apparatus a plurality of times to record a plurality of subsequent stable measurement outputs.
The controller may be configured to average some or all of the stable measurement outputs and subsequent stable measurement outputs.
Of course, in alternative embodiments, alternative mechanisms or configurations or devices or components may be used to vary the load of the current to supply the current to the electromagnet or solenoid 9 in place of the load 39 and switch 41. For example, a variable load such as a variable resistor may be included in a circuit in series or parallel with the electromagnet or solenoid 9 and may interfere with the measurement output by temporarily changing the load of the variable load.
In alternative embodiments, for example, the load 39 may be replaced with an inductance or capacitance, or another electronic component.
While the invention has been described in conjunction with the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. Accordingly, the exemplary embodiments of the invention set forth above are to be considered as illustrative and not limiting. Many variations may be made to the described embodiments without departing from the spirit and scope of the invention.
For the avoidance of any doubt, any theoretical explanation provided herein is intended to enhance the reader's understanding. The inventors do not wish to be bound by any of these theoretical explanations.
Any section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described.
Throughout this specification including the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.
It should be noted that, as used in the specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from "about" one particular value, and/or to "about" another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent "about," it will be understood that the particular value forms another embodiment. The term "about" in relation to a numerical value is optional and means, for example, +/-10%.
Claims (27)
1. An apparatus, comprising:
a weighing apparatus for producing a measurement output indicative of the weight of an object loaded on the weighing apparatus; and
a disturbing element for temporarily disturbing a measurement output of the weighing apparatus when the object is loaded on the weighing apparatus.
2. The apparatus of claim 1, wherein the weighing device is configured to generate a measurement output indicative of a weight of the semiconductor wafer loaded on the weighing device.
3. The apparatus of claim 1 or 2, wherein the interfering element is configured to interfere with the object loaded on the weighing device.
4. The apparatus of any one of the preceding claims, wherein the interfering element is configured to interfere with the weighing device or a component of the weighing device.
5. The apparatus of any one of the preceding claims, wherein the interfering element is configured to change the total weight loaded on the weighing device.
6. The apparatus of claim 1, wherein:
the weighing apparatus includes an electromagnetic coil; and
the interference element comprises a magnet or a solenoid which can be used to interfere with the solenoid of the weighing device.
7. The apparatus of claim 1, wherein:
the weighing apparatus comprises a force-measuring device; and
the disturbance element comprises a magnet or an electromagnetic coil which can be used to disturb the force-measuring device.
8. The apparatus of claim 1, wherein the interfering element comprises a mechanism for temporarily loading additional weight on the weighing device.
9. The device of claim 1, wherein the interfering element comprises a blower for blowing air at or on the object.
10. The apparatus of claim 1, wherein:
the apparatus or weighing device comprises a measurement chamber; and
the disturbing element comprises a mechanism for disturbing the air in the measuring chamber.
11. The apparatus of claim 10, wherein the interfering element comprises a controller configured to temporarily open and then close a lid of the measurement chamber to interfere with air in the measurement chamber.
12. The apparatus of claim 1, wherein the interfering element comprises a mechanism for vibrating the weighing device and/or the object.
13. The apparatus of claim 1, wherein the interfering element comprises a mechanism for mechanically interfering with the object and/or the weighing device.
14. The apparatus of claim 1, wherein the interfering element comprises a device for temporarily interrupting or changing the power supplied to the weighing device.
15. The apparatus of claim 1, wherein the interfering element comprises a controller configured to reset or interrupt a stability algorithm of the weighing device.
16. The apparatus of claim 1, wherein:
the weighing apparatus comprises a position sensor for detecting the position of a component of the weighing apparatus; and
the interference element comprises means for optically or mechanically interfering with the position sensor.
17. The apparatus of claim 1, wherein:
the weighing apparatus comprises a force-measuring device;
the device comprises a circuit for supplying power to the force-measuring device; and
the interfering element includes a mechanism for temporarily changing an electrical characteristic of the circuit.
18. The apparatus of claim 17, wherein the interfering element comprises a mechanism for temporarily changing a load, resistance, capacitance, or inductance of the circuit.
19. The apparatus of any one of claims 1, 17, or 18, wherein:
The weighing apparatus comprises a force-measuring device; and the disturbance element comprises an electronic component and a switch connected in parallel with the force-measuring device.
20. The apparatus of claim 19, wherein the electronic component comprises a load, a resistor, a capacitor, or an inductor.
21. The apparatus of any preceding claim, wherein the apparatus comprises a controller configured to:
recording a steady measurement output of the weighing apparatus with the object loaded on the weighing apparatus;
controlling the disturbance element to temporarily disturb the measurement output of the weighing apparatus with the object loaded on the weighing apparatus; and
a subsequent stable measurement output of the weighing apparatus with the object loaded on the weighing apparatus is recorded.
22. The apparatus of claim 21, wherein the controller is configured to:
repeating the steps of controlling the disturbance element and recording the subsequent stable measurement output a plurality of times; and
averaging at least some of the stable measurement outputs and the subsequent stable measurement outputs.
23. The apparatus of any one of the preceding claims, wherein the weighing device is an electronic balance.
24. Apparatus according to any one of the preceding claims, wherein the weighing device comprises a force-measuring device.
25. The apparatus of any preceding claim, wherein the apparatus comprises a controller configured to calculate the mass of the object based on the measurement output.
26. The apparatus of claim 25, wherein the controller is configured to convert the measurement output to a mass value via application of buoyancy calculations.
27. A method, comprising:
using a weighing apparatus to generate a measurement output indicative of the weight of an object loaded on the weighing apparatus; and
the measurement output of the weighing apparatus is temporarily disturbed when the object is loaded on the weighing apparatus.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GBGB2108212.8A GB202108212D0 (en) | 2021-06-09 | 2021-06-09 | Apparatus comprising a weighing device |
| GB2108212.8 | 2021-06-09 | ||
| PCT/EP2022/059850 WO2022258245A1 (en) | 2021-06-09 | 2022-04-13 | Apparatus comprising a weighing device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117460931A true CN117460931A (en) | 2024-01-26 |
Family
ID=76838937
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202280041459.9A Pending CN117460931A (en) | 2021-06-09 | 2022-04-13 | Device comprising a weighing apparatus |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP4352466A1 (en) |
| KR (1) | KR20220166776A (en) |
| CN (1) | CN117460931A (en) |
| GB (1) | GB202108212D0 (en) |
| TW (1) | TW202314199A (en) |
| WO (1) | WO2022258245A1 (en) |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB0804499D0 (en) * | 2008-03-11 | 2008-04-16 | Metryx Ltd | Measurement apparatus and method |
-
2021
- 2021-06-09 GB GBGB2108212.8A patent/GB202108212D0/en not_active Ceased
-
2022
- 2022-04-13 CN CN202280041459.9A patent/CN117460931A/en active Pending
- 2022-04-13 EP EP22722726.1A patent/EP4352466A1/en active Pending
- 2022-04-13 KR KR1020227019326A patent/KR20220166776A/en unknown
- 2022-04-13 WO PCT/EP2022/059850 patent/WO2022258245A1/en active Application Filing
- 2022-06-07 TW TW111120957A patent/TW202314199A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| GB202108212D0 (en) | 2021-07-21 |
| WO2022258245A1 (en) | 2022-12-15 |
| KR20220166776A (en) | 2022-12-19 |
| EP4352466A1 (en) | 2024-04-17 |
| TW202314199A (en) | 2023-04-01 |
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